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Study is the first to track the development of fragile X-associated tremor/ataxia syndrome

(SACRAMENTO, Calif.) —

Researchers at the UC Davis MIND Institute and the UC Davis Center for Mind and Brain have received a five-year, $3 million grant from the National Institute of Mental Health to conduct the first long-range study of the mental and psychological decline that accompanies the age-related neurological disorder fragile X-associated tremor/ataxia syndrome, or FXTAS.

Susan Rivera

FXTAS first was identified in 2001 by UC Davis MIND Institute Professors Paul and Randi Hagerman. It was discovered after Randi Hagerman, a developmental and behavioral pediatrician, noticed the symptoms in older male family members of the children she treated with fragile X syndrome, the most common genetic cause of intellectual disability and the leading single-gene cause of autism.

FXTAS is a late-onset neurodegenerative disorder. It affects carriers of a small mutation — also called a premutation — of the fragile X mental retardation 1 (FMR1) gene. Characteristics of FXTAS include debilitating balance problems, tremor, memory loss and dementia. It occurs more frequently in male than in female premutation carriers. Prior to its discovery, FXTAS was often misdiagnosed as other neurodegenerative disorders, such as Alzheimer’s or Parkinson's diseases. The scientists said they hope to learn how to better diagnose and treat the condition.

For the first time, researchers will study the progression of the disorder in adult male carriers of the FMR1 premutation between the ages of 40 and 69, comparing them to men of the same age without the mutation. It is not known why, how, or when some individuals become affected with the disorder and others do not, said Susan Rivera, a professor of psychology affiliated with the MIND Institute and the UC Davis Center for Mind and Brain. Rivera is co-principal investigator for the study and will lead the research with David Hessl, co-principal investigator and associate clinical professor of psychiatry and behavioral sciences.

David Hessl

Rivera said she hopes the study will provide critical information about the early markers of neurodegeneration that will aid in identification of patients most in need of preventive care and treatments, as they become available.

“We’ve been studying fragile X premutation carriers of all ages for a number of years now, so we have learned a lot about the brain and behavior of both younger carriers, and those with FXTAS” Rivera said. “But now, for the first time, we will have the ability to bring participants back at intervals, so that we can watch the developmental progression of both their cognition and mental health, as well as track changes in their brains, over time.

“This allows us to start to address two very important questions: what are the ‘warning signs,’ of the onset of FXTAS, and can we identify a developmental trajectory that predicts who will develop FXTAS and who will not?” Rivera said.

The research will be funded by 2R01MH078041. In addition to Hessl, Rivera will collaborate with Flora Tassone, professor of biochemistry and molecular medicine; Emilio Ferrer-Caja, associate professor of psychology; and Randi Hagerman, professor and medical director of the MIND Institute.

At the UC Davis MIND Institute, world-renowned scientists engage in collaborative, interdisciplinary research to find the causes of and develop treatments and cures for autism, attention-deficit/hyperactivity disorder (ADHD), fragile X syndrome, 22q11.2 deletion syndrome, Down syndrome and other neurodevelopmental disorders. For more information, visit mindinstitute.ucdavis.edu